Sanitary Sewer Overflows
A sanitary sewer overflow (SSO) is a wastewater overflow from a sanitary sewer system that poses significant environmental, health and safety risks. Preventing SSOs is essential to ensure safe and unimpeded transport of raw wastewater to Austin Water's wastewater treatment plants.
What Causes an SSO?
SSOs can be caused by anything that obstructs wastewater flow in a sewer. Common causes include a buildup of fats, oils and grease (FOG) in the collection system, as well as household items flushed down toilets — such as disposable wipes (even those marked "flushable") and feminine hygiene products.
When a blockage prevents wastewater from flowing through a pipe, the wastewater may back up and overflow through a manhole, cleanout or drain, potentially reaching the environment, a home or a business.
- How Austin Water Prevents SSOs
Austin Water's Pretreatment Program provides commercial businesses and residents with educational materials on SSO prevention. The program also enforces grease trap requirements for commercial establishments under Chapter 15-10 of the Austin City Code, including:
- Specific minimum grease trap cleaning schedules (§ 15-10-197)
- Prohibited use of certain enzymes, bacteria and other agents in grease traps (§ 15-10-22(23))
- Enforcement of the FOG limit based on a single grab sample (§ 15-10-23)
Businesses whose wastewater practices contribute to an SSO may be required to reimburse Austin Water for related cleanup and repair costs.
- How You Can Help Prevent SSOs
For Businesses
- Sweep floors to remove all trash and debris before washing them down
- Install and maintain baskets, screens and strainers over all sink and floor drains
- Do not use food grinders or disposals — these have been prohibited in commercial kitchens in the Austin Water service area since 2008
See the Grease Trap Maintenance page for a full list of best management practices and grease trap guidance.
For Residents
- Collect small amounts of fats, oils and grease in an empty can or jar. Once cool, seal the container in a bag and place in the trash, or take it to Austin Resource Recovery's Recycle and Reuse Drop-off Center
- Scrape food scraps into a compost or trash bin to minimize garbage disposal use
- Wipe oily pans and dishes with a paper towel before washing and discard the towel in the trash
- Only flush the three Ps: pee, poop and toilet paper
For more information, see the Stop the Grease Blob and Only Flush Toilet Paper pages.